1. Field of the Invention
The present invention pertains to the construction of a manually operated trigger sprayer in which a U-shaped spring is connected to a piston rod by a snap-fit connection. The connection includes a compressable forward end of the piston rod that is pressed through an opening on the forward end of the spring to connect the piston rod to the spring. The rearward end of the spring is connected to the sprayer housing by a curved surface that engages around an exterior surface of the pump chamber.
2. Description of the Related Art
Handheld and hand pumped liquid dispensers commonly known as trigger sprayers are used to dispense many household products and commercial cleaners. Trigger sprayers have been used to dispense household cleaning or cooking liquids and have been designed to selectively dispense the liquids in a spray, stream, or foaming discharge. The trigger sprayer is typically connected to a plastic bottle that contains the liquid dispensed by the sprayer.
A typical trigger sprayer includes a sprayer housing that is connected to the neck of the bottle by either a thread connection or a bayonet-type connection. The sprayer housing is formed with a pump chamber and a vent chamber, a liquid supply passage that communicates the pump chamber with a liquid inlet opening of the sprayer housing, and a liquid discharge passage that communicates the pump chamber with a liquid outlet opening of the sprayer housing. A dip tube is connected to the sprayer housing liquid inlet opening to communicate the pump chamber with the liquid contents of the bottle connected to the trigger sprayer.
A nozzle assembly is connected to the sprayer housing at the liquid outlet opening. Some nozzle assemblies include a nozzle cap that is rotatable relative to the sprayer housing between an “off” position where liquid discharge from the trigger sprayer is prevented, and one or more “on” positions where liquid discharge from the trigger sprayer is permitted. In addition, known nozzle assemblies can affect the liquid discharged by the trigger sprayer to discharge the liquid in a spray pattern, in a stream pattern, or as a foam.
A pump piston is mounted in the sprayer housing pump chamber for reciprocating movement between charge and discharge positions of the piston relative to the pump chamber. When the pump piston is moved to its charge position, the piston is retracted out of the pump chamber. This creates a vacuum in the pump chamber that draws liquid from the bottle, through the dip tube and into the pump chamber. When the pump piston is moved to its discharge position, the piston is moved into the pump chamber. This exerts a force on the liquid in the pump chamber that pumps the liquid from the pump chamber, through the liquid discharge passage of the sprayer housing and out of the trigger sprayer through the nozzle assembly.
A trigger is mounted on the sprayer housing for movement of the trigger relative to the housing. The trigger is operatively connected to the pump piston to cause the reciprocating movement of the pump piston in the pump chamber in response to movement of the trigger. A user's hand squeezes the trigger toward the sprayer housing to move the trigger and move the pump piston toward the discharge position of the piston in the pump chamber. A metal coil spring is typically positioned inside the pump chamber. The spring engages between the pump piston and a surface of the sprayer housing inside the pump chamber. The spring is compressed when the pump piston is moved to the discharge position in the pump chamber. The resilience of the spring pushes the piston back to the discharge position of the piston relative to the pump chamber when the user's squeezing force on the trigger is released.
Inlet and outlet check valves are assembled into the respective liquid supply passage and liquid discharge passage of the trigger sprayer. The check valves control the flow of liquid from the bottle interior volume through the liquid supply passage and into the pump chamber, and then from the pump chamber and through the liquid discharge passage to the nozzle assembly of the trigger sprayer.
In the construction of the typical trigger sprayer discussed above, all of the component parts are constructed of a plastic material except for the metal coil spring in the pump chamber. If it is desired to recycle the plastic material after the useful life of the trigger sprayer, the coil spring must first be removed. Disassembling the sprayer parts to allow for removal of the coil spring detracts from the value of recycling the plastic of the used trigger sprayer.
Trigger sprayers are at times used to dispense liquids that react with metal. The metal coil spring in the pump chamber could cause a reaction in the liquid pumped through the pump chamber. The reaction of the liquid could detract from a desirable characteristic of the liquid. For example, the reaction could detract from the cleaning ability of a cleaning liquid dispensed by the trigger sprayer.
To overcome the disadvantages associated with the use of a metal coil spring in a trigger sprayer, the spring could be constructed of a plastic material. However, trigger sprayers are at times used to dispense liquids that will react with the plastic of a plastic spring in the pump chamber. The reaction could affect the resilience of the plastic spring. This could detract from the ability of the spring to return the pump piston to the charge position in the pump chamber over the useful life of the trigger sprayer.